Athletic endurance
The goal is enhancing endurance, performance and strength in healthy athletes and active adults, including hypoxic and high-altitude training. ACSM/AND/DC Position Stand on Nutrition and Athletic Performance (2016) and the IOC Consensus Statement on Dietary Supplements (2018) list creatine monohydrate, caffeine, dietary nitrate (beetroot juice), beta-alanine and sodium bicarbonate as agents with hard outcomes. Several drugs and supplements (PDE5 inhibitors, hormones, high-dose antioxidants) are marketed for this purpose without an evidence base.
37 drugs
Also known as: athletic performance enhancement, endurance enhancement, ergogenic aids
Drugs used for this condition
- ACreatine monohydrateAdd-on therapy · Dietary supplements, sports nutraceuticals (local classification)Creatine monohydrate is the most evidence-based sports supplement for strength and short-duration power. Meta-analyses (Lanhers 2017, Branch 2003, Kreider 2017) based on more than 500 RCTs confirm 8–14% increase in 1-RM squat, 5–12% in bench press, and 1–2 kg lean mass gain over 4–12 weeks of training at 3–5 g/day. Predominant effect is on anaerobic work (strength sports, sprint, combat); aerobic and marathon performance gain is minimal. IOC, ISSN, NCAA, and AIS guidelines list creatine as evidence-based and safe (AIS category A).
- BBeta-alanineAdd-on therapy · Non-essential beta-amino acid, carnosine precursor. Supplement with IOC 2018 proven efficacy for 1-4 minute anaerobic performanceBeta-alanine is one of the few sports supplements with relatively convincing evidence. Saunders 2017 (BJSM) meta-analysis of 40 RCTs in 1461 subjects: beta-alanine 4–6 g/day × 4–12 weeks improves anaerobic performance by 2.85% in 1–4 minute exercise bouts (100–200 m swimming, 2000 m rowing, 4 km cycling, 1500 m running). Effect on shorter (<1 min) and longer (>10 min) exercises is minimal. IOC consensus statement 2018 included beta-alanine in the list of 5 sports supplements with proven efficacy (alongside creatine, caffeine, bicarbonate, nitrates). ISSN 2015 recommends beta-alanine 4–6 g/day × at least 4 weeks to increase intramuscular carnosine. For healthy non-athletes and aerobic training without anaerobic component the effect is not significant.
Marketing claims without evidence base
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
- CBeetroot juice / dietary nitrate (Beta vulgaris)Not recommended · Food product rich in inorganic nitrate; sold as a sports supplement and a «biohack» BP-lowering aid; not registered as a medicine by AEMPSBeetroot juice is one of the most studied ergogenic supplements in sports science. The Jones 2018 review describes an average 1–3% improvement in time-to-exhaustion in recreational and sub-elite athletes after acute or short-term nitrate loading of 300–600 mg, 2–3 hours before exertion. In elite athletes with high baseline NO bioavailability the effect becomes negligible. Biohacker blogs promote beetroot as a «secret weapon for marathoners», yet the real gain is modest and unstable and is easily wiped out by poor sleep or feeding strategy. AESAN and AEMPS have not registered beetroot juice as an ergogenic aid. Pre-race chlorhexidine mouthwash abolishes the effect because antibacterial mouth care blocks the nitrate-to-nitrite step.
- DAclidiniumNot recommended · Long-acting muscarinic antagonist for inhalation (LAMA)Aclidinium is sometimes offered outside its licensed use «for endurance gains» in people without COPD. There is no benefit to expect: bronchodilation raises FEV1 only when baseline obstruction exists, and in a healthy person the airways are already open. WADA does not prohibit the drug. No convincing evidence supports an endurance benefit, and this is a prescription inhaler with its own adverse effects (dry mouth, rarely paradoxical bronchospasm), so there is no reason to take it without an indication. If aclidinium is suggested «to improve cardio» without a COPD diagnosis, discuss it with a second specialist.
- DAshwagandha (Withania somnifera)Not recommended · Dietary supplements, plant adaptogens (local classification)Ashwagandha is marketed in fitness communities for muscle strength, VO2max, and testosterone enhancement. Five to seven small RCTs (Wankhede 2015, Ziegenfuss 2018) in trained men aged 18–45 show 1-RM squat and bench press gains of 10–15% and testosterone increases of 14–22% versus placebo. Studies are small (40–60 participants), last 8–12 weeks, and some were industry-funded. IOC, AIS, and ACSM sports nutrition guidelines do not list ashwagandha as an evidence-based ergogenic agent.
- DBetaine (trimethylglycine, TMG)Not recommended · Methyl donor; agent for the alternative homocysteine remethylation pathwaySports marketing positions betaine as a «legal anabolic equivalent»: doses of 2.5 g/day allegedly improve strength and endurance. A 2017 Cholewa meta-analysis showed statistically significant but clinically modest strength improvement (about 2%) in untrained men; in trained athletes the effect is not reproducible. International sports federations do not recognise the drug as ergogenic. AEMPS and AESAN consider performance-enhancement claims unsubstantiated.
- DCordyceps (Cordyceps sinensis, Cordyceps militaris)Not recommended · Medicinal mushroom of Tibetan and Chinese medicine, supplement. AEMPS does not register as medicineCordyceps is a popular «natural preworkout» in endurance sports (running, cycling, swimming) with the legend of Chinese runners breaking world records in 1993. Evidence in young healthy athletes: small RCTs showed heterogeneous VO2max and time-to-exhaustion results. In healthy elderly volunteers (Chen 2010) 333 mg three times daily of CS-4 × 12 weeks showed metabolic and ventilatory threshold improvement. EFSA approved no physical performance claim for cordyceps. IOC consensus statement 2018 on sports supplements does not include cordyceps.
- DD-riboseNot recommended · Pentose monosaccharide; complemento alimenticio with a claimed role in energy metabolismD-ribose is positioned as a training supplement that «accelerates ATP recovery after exercise». The ISSN 2018 position stand explicitly classifies D-ribose among supplements with insufficient evidence – RCTs in trained athletes show no advantage over placebo for strength, power or time to exhaustion. ISSN further notes that the product causes hypoglycaemia on an empty stomach and does not justify its cost.
- DEleutherococcus senticosus («Siberian ginseng»)Not recommended · Plant adaptogen, supplement. In EU – traditional herbal medicinal product (EMA HMPC); OTC tincture in RussiaEleutherococcus is sold to athletes and gym-goers as a «natural preworkout». Some RCTs showed moderate VO2max and time-to-exhaustion improvements at 800–1200 mg/day of standardised extract; others no effect. EFSA 2010 approved no physical performance claim. IOC consensus statement 2018 on sports supplements does not include eleutherococcus in the proven-efficacy list (creatine, caffeine, beta-alanine, bicarbonate, nitrates are approved).
- DL-arginineNot recommended · Conditionally essential amino acid, NO precursor. Sport and cardio-biohacking supplement. AEMPS does not register as medicineL-arginine is sold in pre-workout formulas as a «pump and endurance» product on the NO-mediated vasodilation hypothesis. The Alvares 2011 (Sports Med) systematic review of exercise RCTs found mixed results (some acute and chronic trials positive, others not) and judged it premature to recommend arginine as ergogenic. Doses up to 20 g are well tolerated. EFSA 2014 approved no physical performance claim. IOC consensus statement 2018 does not include L-arginine in the proven-efficacy list. L-citrulline (see card) raises plasma arginine more effectively by bypassing intestinal first-pass.
- DL-citrulline (free form and L-citrulline malate for sports formulas)Not recommended · Non-essential amino acid and urea-cycle intermediate. Normally produced in liver and gut from glutamine and converted in plasma to L-arginine and then nitric oxide (NO). Supplements market it as a «natural Viagra alternative», a «pump» agent for bodybuilders (vasodilation and muscle blood flow), and a remedy for blood pressure and cardiovascular health. Neither AEMPS nor EMA register it as a medicine; a specialty product (citrulline malate) exists for mitochondrial disorders and urea-cycle defects, but it is a specialised drug, not a supplement. AESAN classifies regular L-citrulline supplements as complementos alimenticios. FDA has issued no supplement approval.L-citrulline is widely sold in pre-workout formulas promising «increased pump» and «better endurance» via NO-mediated vasodilation. Small RCTs are mixed: some show a moderate effect of citrulline malate 6–8 g/day on high-intensity performance and reduced post-exercise muscle soreness, others show none; aerobic endurance data are conflicting. EFSA 2024 recognised L-citrulline as safe; no physical performance claim approved. IOC consensus statement 2018 on sports supplements does not include L-citrulline in the proven-efficacy list.
- DLevocarnitine (L-carnitine)Not recommended · Amino acid derivative; cofactor for long-chain fatty acid transport into mitochondriaL-carnitine is marketed as an endurance and recovery supplement. In 2011 EFSA rejected several proposed claims: «improved fat utilisation as fuel», «increased endurance», «reduced recovery time». The ISSN 2018 position stand does not list L-carnitine among ergogenic aids with convincing evidence. Some studies with L-carnitine tartrate report lower muscle damage markers, but the effect size is small and clinically meaningful performance benefit has not been shown.
- DNicotinamide mononucleotide (NMN)Not recommended · Dietary supplements, NAD+ precursors (local classification)NMN (nicotinamide mononucleotide) is a NAD+ precursor sold as a supplement for energy, recovery, and athletic endurance. Convincing human evidence that NMN improves endurance or performance is lacking: the trials are small and inconsistent. Endurance responds more reliably to consistent aerobic training, enough sleep, and solid nutrition, and NMN does not replace any of that.
- DRhodiola rosea (golden root)Not recommended · Plant adaptogen, supplement. In EU – traditional herbal medicinal product per EMA HMPC monographRhodiola is sold as a «natural preworkout» promising improved endurance and reduced training fatigue. Small RCTs in 20–30 subjects showed heterogeneous results: some demonstrated moderate VO2max and time-to-exhaustion improvements on cycle ergometry, others no effect. EFSA 2010 approved no physical performance claim for rhodiola. In IRONMAN/UCI Pro endurance athletes, it is not on the IOC consensus statement 2018 list of sports supplements (only creatine, caffeine, beta-alanine, bicarbonate, nitrates are approved). If rhodiola was recommended as a substitute for a supervised training plan, consider seeking a second opinion from a sports physician.
- DSchisandra chinensis (magnolia berry)Not recommended · Plant adaptogen, supplement. In EU – EMA HMPC assessment 2024; OTC tincture in RussiaSchisandra chinensis is a plant whose extract is added to supplements as an adaptogen and marketed for improving athletic endurance. Convincing benefit for this use has not been shown – there is no solid evidence that it increases endurance in athletes. What actually improves endurance is regular training, adequate recovery and balanced nutrition.
- DTaurineNot recommended · Sulfur-containing amino acid, supplement and energy-drink ingredient. In Russia registered as a medicine (Dibicor) for T2DM and CHFTaurine is widely used in pre-workout formulas and energy drinks as an «endurance booster». Meta-analyses on sports taurine (Waldron 2018, J Strength Cond Res) showed a small ambiguous effect on time trials in rowing and running in endurance athletes; no benefit in strength sports and at maximal loads. EFSA 2009 approved no physical performance claim. In healthy non-athletes no significant effect on endurance is recorded. The energy drink effect is attributed mostly to caffeine (80–160 mg per can), not taurine.
- DUbidecarenone (coenzyme Q10)Not recommended · Other cardiac preparations. Coenzyme Q10Ubidecarenone (coenzyme Q10) is a substance the body makes on its own; in supplements it's marketed as a way to boost athletic endurance and speed up recovery. Convincing benefit for this use hasn't been shown – there's no solid evidence that coenzyme Q10 improves endurance in healthy people. Endurance grows from regular training, enough sleep, and balanced nutrition, which are the approaches that actually deliver.
- FAbirateroneNot recommended · Androgen biosynthesis inhibitorsFor endurance or recovery, abiraterone is counterproductive and unsafe. It is a CYP17 inhibitor that lowers testosterone to castrate levels, so in a healthy athlete it produces iatrogenic hypogonadism (fatigue, loss of muscle mass and strength, anemia), the opposite of the intended goal. Some AAS users take it to block endogenous androgens, but no approved athlete indication exists. The AEMPS Ficha Técnica confines the drug to metastatic prostate cancer with prednisone; use without a glucocorticoid causes mineralocorticoid syndrome (hypokalemia, edema, hypertension), plus hepatotoxicity and adrenal-insufficiency risk.
- FAllopurinolNot recommended · Xanthine oxidase inhibitorsAllopurinol is a xanthine oxidase inhibitor. It is prescribed for chronic gout with hyperuricemia and for some conditions with uric acid overproduction (tumor lysis syndrome, uric acid nephrolithiasis) (ACR 2020, EULAR 2017). In sports circles, allopurinol is occasionally promoted to reduce oxidative stress and improve recovery. In athletes without gout, a few studies of prophylactic use do exist (including an RCT in soccer players), but they show no benefit for endurance or performance, only changes in surrogate muscle-damage markers. The drug has serious risks: severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS), especially in HLA-B*5801 carriers, hepatotoxicity, and hematological disturbances. If allopurinol was prescribed to an athlete for recovery, consider seeking a second opinion.
- FAnastrozoleNot recommended · Third-generation non-steroidal aromatase inhibitorAnastrozole is used by amateur bodybuilders and self-administered AAS users for suppressing testosterone-to-estrogen aromatization. ASCO 2022 and the AEMPS Ficha Técnica confine anastrozole to hormone-receptor-positive breast cancer in postmenopausal women. Approved indications in men or athletes do not exist. Use causes marked bone mineral density loss (FDA Drug Safety Communication 2010), arthralgia, dyslipidemia and cardiovascular risk.
- FBicalutamideNot recommended · Non-steroidal antiandrogenBicalutamide is used by amateur AAS cyclers for androgen blockade in post-cycle therapy. NCCN 2024 and the AEMPS Ficha Técnica confine bicalutamide to prostate cancer. Approved athlete indications do not exist. Use causes gynecomastia, hepatotoxicity (FDA boxed warning) and decreased libido without proven benefit.
- FExemestaneNot recommended · Steroidal aromatase inhibitorsExemestane is used by amateur bodybuilders and AAS users as a steroidal aromatase inhibitor. ASCO 2022 and the AEMPS Ficha Técnica confine exemestane to hormone-receptor-positive breast cancer in postmenopausal women. Approved indications in male athletes do not exist. Use causes marked bone mineral density loss, arthralgia, hypertension and psychiatric effects.
- FFormoterolNot recommended · Long-acting selective β2-agonist with rapid onset (rapid-onset LABA)Formoterol is used off-label by athletes and fitness influencers for «endurance gains» via β2-receptor stimulation. The hypothetical anabolic and metabolic effect in people without asthma is not supported by quality data. WADA 2024 lists formoterol as prohibited but allows inhalations up to 54 mcg/day with urine peak below 40 ng/mL (TUE with documented asthma). Biohacking above these limits produces tachycardia, tremor, hypokalaemia and arrhythmias. If formoterol is suggested without an asthma diagnosis to «improve cardio», consider seeking a second opinion.
- FIpratropium bromideNot recommended · Short-acting muscarinic antagonist for inhalation (SAMA)Ipratropium is offered as a «mild bronchodilator for training» without a diagnosis of asthma or COPD. In healthy people inhalation produces no meaningful FEV1 gain or performance improvement. WADA does not prohibit the drug, but chronic anticholinergic exposure in young adults – dry mouth, impaired thermoregulation during exercise – is unjustified. If ipratropium is suggested for «better breathing during training» without obstructive disease, consider seeking a second opinion.
- FIsosorbide mononitrateNot recommended · Long-acting organic nitrateIsosorbide mononitrate is a long-acting organic nitrate. It is prescribed for angina prophylaxis (ESC 2024). In sports circles, isosorbide mononitrate is occasionally promoted to improve blood flow to muscles. In healthy athletes without ischemic heart disease, no clinical studies of prophylactic use exist. The drug has specific risks: headache (common, marked), hypotension with syncope, tolerance with regular use, and dangerous blood pressure drop combined with PDE5 inhibitors (strictly contraindicated). If isosorbide mononitrate was prescribed to an athlete, consider seeking a second opinion.
- FIvabradineNot recommended · Selective If channel inhibitor of the sinoatrial nodeIvabradine is a selective sinus node If-channel inhibitor that reduces heart rate. It is prescribed for stable angina and heart failure with reduced ejection fraction (ESC 2024). In sports circles, ivabradine is occasionally promoted for pulse control during cardio in people without heart failure. In healthy athletes, no clinical studies of prophylactic use exist; such prescription can mask cardiovascular symptoms and is dangerous. The drug has specific risks: bradycardia, phosphenes (flashes of bright light in the visual field, in 14% of patients), atrial fibrillation, and conduction disturbances. Ivabradine is on the WADA Prohibited List in competition. If ivabradine was prescribed to an athlete for training, consider seeking a second opinion.
- FLetrozoleNot recommended · Third-generation non-steroidal aromatase inhibitorLetrozole is used by amateur bodybuilders and AAS users as a more potent aromatase inhibitor. ASCO 2022 and the AEMPS Ficha Técnica confine letrozole to hormone-receptor-positive breast cancer. Approved indications in male athletes do not exist. Use causes marked bone mineral density loss, arthralgia, hypercholesterolemia, psychiatric effects and cardiovascular risk.
- FMeldoniumNot recommended · Metabolic agents (local classification). Russian and Latvian development.Evidence tier F (and prohibited). WADA added meldonium to the Prohibited List on 1 January 2016 after pre-listing surveillance found the drug in samples from more than 180 athletes at the 2015 European Games and in numerous post-Soviet competitors across endurance sports. A high-profile sanction followed: tennis player Maria Sharapova received a provisional ban in March 2016. The drug is not approved as an ergogenic aid by any regulator. Independent RCTs in healthy athletes are absent. Use of meldonium by competitive athletes triggers anti-doping sanctions regardless of intent.
- FMethylthioninium chloride (methylene blue)Not recommended · Antidotes (V03AB17). The drug has one FDA-approved indication – methaemoglobinaemia. Biohacker use is off-label.In biohacker sports self-administration, methylene blue is taken pre-workout as an «aerobic endurance booster». Published RCTs in athletes with VO2max or time-to-exhaustion endpoints do not exist. IOC, AIS, and ACSM guidelines do not list methylene blue.
- FNitroglycerinNot recommended · Organic nitrateNitroglycerin is an organic nitrate and potent vasodilator. It is prescribed for acute angina relief and acute left heart failure (ESC 2024). In sports circles, nitroglycerin is occasionally promoted to improve blood flow to muscles before training. In healthy athletes without ischemic heart disease, no clinical studies of prophylactic use exist, and such use is dangerous. The drug has specific risks: severe hypotension with syncope, headache (common, marked), tolerance with regular use, and dangerous blood pressure drop combined with PDE5 inhibitors (sildenafil, tadalafil – strictly contraindicated). If nitroglycerin was prescribed to an athlete for training, consider seeking a second opinion.
- FPhenylpiracetam (fonturacetam)Not recommended · Nootropics (local classification). Russian development.Phenylpiracetam in amateur and professional sport was used as an endurance and cognitive stimulant. WADA added the drug to the Prohibited List effective 1 January 2010 (S6 – stimulants). A notable case was the disqualification of skier Alena Kauf (2017) for fonturacetam use. IOC, AIS, and ACSM sports nutrition guidelines do not list the drug.
- FSalmeterolNot recommended · Long-acting selective β2-agonist (LABA, bronchodilator)Salmeterol is used off-label by fitness influencers and athletes without asthma for «endurance gains» via skeletal-muscle β2 stimulation. The hypothesized anabolic effect is not confirmed: systematic reviews find no quality evidence. The drug appears on the WADA 2024 Prohibited List; exemption is possible only with documented asthma under a TUE and within strict dose limits. Real biohacking risks: tachycardia, tremor, hypokalaemia, QT prolongation. If salmeterol is suggested without an asthma diagnosis as a way to «boost cardio», consider seeking a second opinion.
- FSildenafilNot recommended · Phosphodiesterase type 5 inhibitors (PDE5)Sildenafil is marketed for athletic performance and endurance in healthy athletes – particularly during hypoxic or high-altitude training – via systemic vasodilation and improved pulmonary blood flow. WADA has considered PDE5 inhibitors for the Prohibited List since 2009; as of 2026 they are not on the list. ACSM and IOC Medical Commission do not describe clinical indications for sildenafil in healthy athletes – the evidence base for improving general or anaerobic performance in healthy people is absent.
- FTadalafilNot recommended · Phosphodiesterase type 5 (PDE-5) inhibitorTadalafil is a long-acting phosphodiesterase-5 (PDE5) inhibitor. It is prescribed for erectile dysfunction, benign prostatic hyperplasia, and pulmonary arterial hypertension (AEMPS Ficha Técnica). In sports circles, tadalafil is promoted to improve pulmonary gas exchange and physical endurance in healthy athletes. Clinical studies in healthy athletes are small and conflicting. The drug has specific risks: headache, facial flushing, nasal congestion, dyspepsia, muscle pain, visual disturbances (bluish tint), rarely non-arteritic anterior ischemic optic neuropathy (vision loss risk), and sudden hearing loss. It is dangerous combined with nitrates (sharp blood pressure drop). If tadalafil is used for training, consider seeking a second opinion.
- FTamoxifenNot recommended · Selective estrogen receptor modulator (SERM)Tamoxifen is used by amateur bodybuilders and AAS users in post-cycle therapy to block estrogen receptors and restore endogenous testosterone production. ASCO 2022 and the AEMPS Ficha Técnica confine tamoxifen to hormone-receptor-positive breast cancer and risk reduction in high-risk women. Approved indications in male athletes do not exist. Use carries venous thromboembolism, endometrial cancer (FDA boxed warning) and thromboembolic stroke risk.
- FTiotropiumNot recommended · Long-acting muscarinic antagonist for inhalation (LAMA)Tiotropium is offered off-label as a «training bronchodilator» without a COPD or asthma diagnosis. In healthy individuals there is no meaningful FEV1 gain: bronchodilation provides benefit only when baseline obstruction is present. WADA does not prohibit tiotropium, but use without a diagnosis means unjustified chronic anticholinergic exposure: dry mouth, urinary retention, raised intraocular pressure in susceptible patients. Beers Criteria 2023 lists inhaled LAMAs among anticholinergic-burden drugs in older adults. If tiotropium is suggested to «boost breathing capacity» without obstructive disease, consider seeking a second opinion.
- FVardenafilNot recommended · Phosphodiesterase type 5 (PDE-5) inhibitorVardenafil is a phosphodiesterase-5 (PDE5) inhibitor. It is prescribed for erectile dysfunction (AEMPS Ficha Técnica). In sports circles, vardenafil is promoted to improve blood flow and physical endurance in healthy athletes. Clinical studies in healthy athletes are insufficient. The drug has specific risks: headache, facial flushing, nasal congestion, dyspepsia, QT prolongation, visual disturbances, and is dangerous combined with nitrates. If vardenafil is used for training, consider seeking a second opinion.
How to read tiers A–F
Evidence tiers belong to the drug-indication pair, not to the drug as a whole: the same substance can be A for one condition and F for another.
- AStrong evidence – first or second line in international guidelines
- BRecommended in selected cases
- CStudy data contradict each other
- DBenefit not proven, no documented harm
- FDocumented harm, or risk without benefit